step line numbers are recorded when protocol is loaded (#65) (#121)

Cargo.toml

@@ -15,7 +15,7 @@ path = "src/main.rs"
 nix = "*"
 libc = "*"
 tempdir = "*"
-yaml-rust = "*"
+yaml-rust = { git = "https://github.com/originate/yaml-rust", rev = "5216abe1f7d24ccd17a3b1b1e56c0114758d5ed7" }
 linked-hash-map = "*"
 bincode = "*"
 quale = "*"

src/protocol/marker.rs

@@ -0,0 +1,25 @@
+use yaml_rust;
+
+#[derive(Clone, Copy, Debug, Eq, PartialEq)]
+pub struct Marker {
+    pub line: usize,
+    pub col: usize,
+}
+
+impl<'a> From<&'a yaml_rust::Marker> for Marker {
+    fn from(marker: &'a yaml_rust::Marker) -> Self {
+        Marker {
+            line: marker.line(),
+            col: marker.col(),
+        }
+    }
+}
+
+impl From<yaml_rust::Marker> for Marker {
+    fn from(marker: yaml_rust::Marker) -> Self {
+        Marker {
+            line: marker.line(),
+            col: marker.col(),
+        }
+    }
+}